# K index

From AMS Glossary

## K index

(

*Also called*George's index.) A stability index that is a measure of thunderstorm potential based on temperature lapse rate, moisture content of the lower troposphere, and the vertical extent of the moist layer.The K index is determined by the following equation: where

*T*is the temperature and*T'***d****is the dewpoint in degrees Celsius at the pressure levels indicated. The higher (positive) the K index, the greater the likelihood of thunderstorm development.**